module Neo4j
  module Rails
    class Model
      include Neo4j::NodeMixin
      include ActiveModel::Validations
      include ActiveModel::Dirty
      include ActiveModel::MassAssignmentSecurity

      extend ActiveModel::Naming
      extend ActiveModel::Callbacks
      extend Neo4j::Validations::ClassMethods
      extend TxMethods
#      extend ClassMethods::Relationship

      define_model_callbacks :create, :save, :update, :destroy


      UniquenessValidator = Neo4j::Validations::UniquenessValidator

      class RecordInvalidError < RuntimeError
        attr_reader :record

        def initialize(record)
          @record = record
          super(@record.errors.full_messages.join(", "))
        end
      end

      # --------------------------------------
      # Initialize
      # --------------------------------------

      def initialize(*)
      end

      def init_on_create(*args) # :nodoc:
        super()
        self.attributes=args[0] if args[0].respond_to?(:each_pair)
        @_created_record = true
      end

      # --------------------------------------
      # Identity
      # --------------------------------------

      def id
        neo_id.nil? ? nil : neo_id.to_s
      end

      def to_param
        persisted? ? neo_id.to_s : nil
      end

      # Returns an Enumerable of all (primary) key attributes
      # or nil if model.persisted? is false
      def to_key
        persisted? ? [:id] : nil
      end


      # enables ActiveModel::Dirty and Validation
      def method_missing(method_id, *args, &block)
        if !self.class.attribute_methods_generated?
          self.class.define_attribute_methods(self.class._decl_props.keys)
          # try again
          send(method_id, *args, &block)
        end
      end

      # redefine this methods so that ActiveModel::Dirty will work
      def []=(key, new_value)
        key = key.to_s
        unless key[0] == ?_
          old_value = self.send(:[], key)
          attribute_will_change!(key) unless old_value == new_value
        end
        Neo4j::Rails::Transaction.running? ? super : Neo4j::Rails::Transaction.run { super }
      end

      def attribute_will_change!(attr)
        begin
          value = __send__(:[], attr)
          value = value.duplicable? ? value.clone : value
        rescue TypeError, NoMethodError
        end
        changed_attributes[attr] = value
      end


      def read_attribute_for_validation(key)
        respond_to?(key) ? send(key) : self[key]
      end

      def attributes=(values)
        sanitize_for_mass_assignment(values).each do |k, v|
          if respond_to?("#{k}=")
            send("#{k}=", v)
          else
            self[k] = v
          end
        end
      end


      # Updates this resource with all the attributes from the passed-in Hash and requests that the record be saved.
      # If saving fails because the resource is invalid then false will be returned.
      def update_attributes(attributes)
        self.attributes=attributes
        save
      end

      def update_attributes!(attributes)
        self.attributes=attributes
        save!
      end

      def update_nested_attributes(rel_type, clazz, has_one, attr, options)
        allow_destroy, reject_if = [options[:allow_destroy], options[:reject_if]] if options

        if new?
          # We are updating a node that was created with the 'new' method.
          # The relationship will only be kept in the Value object.
          outgoing(rel_type)<<clazz.new(attr) unless reject_if?(reject_if, attr)
        else
          # We have a node that was created with the #create method - has real Neo4j relationships
          # does it exist ?
          found = if has_one
            # id == nil that means we have a has_one relationship
                    outgoing(rel_type).first
                  else
                    # do we have an ID ?
                    id = attr[:id]
                    # this is a has_n relationship, find which one we want to update
                    id && outgoing(rel_type).find { |n| n.id == id }
                  end

          # Check if we want to destroy not found nodes (e.g. {..., :_destroy => '1' } ?
          destroy = attr[:_destroy] && attr[:_destroy] != '0'

          if found
            if destroy
              found.destroy if allow_destroy
            else
              found.update_attributes_in_tx(attr) # it already exist, so update that one
            end
          elsif !destroy && !reject_if?(reject_if, attr)
            new_node = clazz.new(attr)
            saved = new_node.save
            outgoing(rel_type) << new_node if saved
          end
        end
      end

      def reject_if?(proc_or_symbol, attr)
        return false if proc_or_symbol.nil?
        if proc_or_symbol.is_a?(Symbol)
          meth = method(proc_or_symbol)
          meth.arity == 0 ? meth.call : meth.call(attr)
        else
          proc_or_symbol.call(attr)
        end
      end

      def delete
        super
        @_deleted = true
        @_persisted = false
      end

      def save
        valid = valid?
        if valid
          # if we are trying to save a value then we should create a real node
          valid = _run_save_callbacks { create_or_update_node }
          @_created_record = false
          true
        else
          # if not valid we should rollback the transaction so that the changes does not take place.
          # no point failing the transaction if we have created a model with 'new'
          Neo4j::Rails::Transaction.fail if Neo4j::Rails::Transaction.running? && !_java_node.kind_of?(Neo4j::Rails::Value)
          false
        end
        valid
      end

      def create_or_update_node
        valid = true
        if _java_node.kind_of?(Neo4j::Rails::Value)
          node = Neo4j::Node.new(props)
          valid = _java_node.save_nested(node)
          init_on_load(node)
          init_on_create
        end

        if  new_record?
          _run_create_callbacks { clear_changes }
        else
          _run_update_callbacks { clear_changes }
        end
        valid
      end

      def clear_changes
        @previously_changed = changes
        @changed_attributes.clear
      end

      def save!
        raise RecordInvalidError.new(self) unless save
      end

      # Returns if the record is persisted, i.e. it’s not a new record and it was not destroyed
      def persisted?
        !new_record? && !destroyed?
      end

      def to_model
        self
      end

      # Returns true if this object hasn’t been saved yet — that is, a record for the object doesn’t exist yet; otherwise, returns false.
      def new_record?()
        # it is new if the model has been created with either the new or create method
        new? || @_created_record == true
      end

      def new?
        _java_node.kind_of?(Neo4j::Rails::Value)
      end

      def del
        @_deleted = true
        super
      end

      def destroy
        _run_update_callbacks { del }
      end

      def destroyed?()
        @_deleted
      end

      tx_methods :destroy, :create_or_update_node, :update_attributes, :update_attributes!

      # --------------------------------------
      # Class Methods
      # --------------------------------------

      class << self
        extend TxMethods

        # returns a value object instead of creating a new node
        def new(*args)
          wrapped = self.orig_new
          value = Neo4j::Rails::Value.new(wrapped)
          wrapped.init_on_load(value)
          wrapped.attributes=args[0] if args[0].respond_to?(:each_pair)
          wrapped
        end

        # Handle Model.find(params[:id])
        def find(*args)
          if args.length == 1 && String === args[0] && args[0].to_i != 0
            load(*args)
          else
            hits = super
            # We need to save this so that the Rack Neo4j::Rails:LuceneConnection::Closer can close it
            Thread.current[:neo4j_lucene_connection] ||= []
            Thread.current[:neo4j_lucene_connection] << hits
            hits
          end
        end

        def load(*ids)
          result = ids.map { |id| Neo4j::Node.load(id) }
          if ids.length == 1
            result.first
          else
            result
          end
        end


        alias_method :_orig_create, :create

        def create(*)
          model = super
          model.save
          model
        end

        def create!(*args)
          model = _orig_create(*args)
          model.save!
          model
        end

        tx_methods :create, :create!


        def transaction(&block)
          Neo4j::Rails::Transaction.run &block
        end

        def accepts_nested_attributes_for(*attr_names)
          options = attr_names.pop if attr_names[-1].is_a?(Hash)

          attr_names.each do |association_name|
            rel = self._decl_rels[association_name.to_sym]
            raise "No relationship declared with has_n or has_one with type #{association_name}" unless rel
            to_class = rel.to_class
            raise "Can't use accepts_nested_attributes_for(#{association_name}) since it has not defined which class it has a relationship to, use has_n(#{association_name}).to(MyOtherClass)" unless to_class
            type = rel.namespace_type
            has_one = rel.has_one?

            send(:define_method, "#{association_name}_attributes=") do |attributes|
              if has_one
                update_nested_attributes(type, to_class, true, attributes, options)
              else
                if attributes.is_a?(Array)
                  attributes.each do |attr|
                    update_nested_attributes(type, to_class, false, attr, options)
                  end
                else
                  attributes.each_value do |attr|
                    update_nested_attributes(type, to_class, false, attr, options)
                  end
                end
              end
            end
            tx_methods("#{association_name}_attributes=")
          end
        end

      end

    end

  end
end